What is stream piracy?

Stream piracy refers to a geological process where one stream captures the flow of another stream, typically occurring through headward erosion. This is when a stream erodes its headwaters, which are the beginning sections of the watercourse, and gradually advances upstream. During this process, the eroding stream may intersect with another stream, diverting its flow into its own channel. This often leads to a significant alteration of the landscape and can create new drainage patterns.

The process of headward erosion is facilitated by various factors, including the stream's gradient and the geology of the surrounding area, which can affect how easily the stream can erode its banks and bed. This phenomenon effectively changes the boundaries of watersheds, which can have broader ecological impacts. Understanding stream piracy helps in comprehending river dynamics and landscape evolution over time.